fix: increase default cuckoo filter fingerprint size (#2636)

Calculate the default fingerprint size from the `f ≥ log2(1/ε) + log2(2b)`
equation from the cucko filter paper.

Also lowers the reliable threshold to 90% from 95% as sometimes we
go over the threshold for smaller filter sizes.

Author: achingbrain

packages/utils/src/filters/cuckoo-filter.ts

@@ -150,7 +150,7 @@ export class CuckooFilter implements Filter {
   }
 
   get reliable (): boolean {
-    return Math.floor(100 * (this.count / this.filterSize)) <= 95
+    return Math.floor(100 * (this.count / this.filterSize)) <= 90
   }
 }
 
@@ -182,7 +182,7 @@ export function optimize (maxItems: number, errorRate: number = 0.001): CuckooFi
 
   // https://stackoverflow.com/questions/57555236/how-to-size-a-cuckoo-filter/57617208#57617208
   const filterSize = Math.round(maxItems / load)
-  const fingerprintSize = Math.min(Math.ceil(Math.log(filterSize / bucketSize)) + 2, MAX_FINGERPRINT_SIZE)
+  const fingerprintSize = Math.min(Math.ceil(Math.log2(1 / errorRate) + Math.log2(2 * bucketSize)), MAX_FINGERPRINT_SIZE)
 
   return {
     filterSize,